Switch actuator for an electronic cooking device

ABSTRACT

A spring biased door arm pivoted at one end to a door for an enclosure includes a protrusion on its lower side normally engaging a door switch to put it in the closed position. The protrusion responds to the opening of the door to ride on a roller normally contacted by the door arm, for causing the protrusion to disengage from the switch to deactuate a device such as a magnetron used for electronic cooking.

D Umted States Patent 1151 3,639,717

Mochizuki Feb. 1, 1972 [54] SWITCH ACTUATOR FOR AN 3,329,795 7/1967 Long ..219/10.55 ELECTRONIC CQOKING DEVICE 3,168,637 2/1965 Lamb ...219ll0.55 2,907,859 10/1959 Walkoe ..2l9/413 X [72] Inventor: Masayuki Mochizuki, Shizuoka, Japan Primary ExaminerH. 0. Jones [73] Asslgnee' Mnsublshl Denkl Kabushikl Kmsha AtlorneyRobert E. Burns and EmmanuelJ. Lobato Tokyo, Japan [22] Filed: Sept. 8, 1970 [57] ABSTRACT {2}} A l N 70,294 A spring biased door arm pivoted at one end to a door for an enclosure includes a protrusion on its lower side normally engaging a door switch to put it in the closed position. The 11.8. CI. protrusion responds to the opening of {he door to ride on a [51] lnt.Cl. ..I-I0lh 3/02 ll ll contacted by the door arm, for causing the Field of Search l 72 5 413 protrusion to disengage from the switch to deactuate av device such as a magnetron used for electronic cooking. [56] References Cited 2 Claims, 4 Drawing Flgures UNITED STATES PATENTS 3,480,753 11/1969 Wilson et al ..219/10.55

PATENTEUFEB H972 3.639.717

PRIOR ART M 30 24 20a I I as 20 SWITCH ACTUATOR FOR AN ELECTRONIC COOKING DEVICE BACKGROUND OF THE INVENTION This invention relates to an electronic cooking device, and more particularly to improvements in a mechanism for a door switch controlled by a door hinged to such a device.

Electronic cooking devices are operative to heat and cook food through the utilization of high-frequency energy. Large quantities of such high-frequency energy must not be permitted to leak from the heating compartment disposed in the device because of possible radiation damage to the human body. For this reason, there have been heretofore proposed various attempts to prevent the high-frequency energy from leaking through the periphery of the heating compartment and especially from the peripheral edge of the openable door therefor. Furthennore, such devices have been operatively coupled to the door switch, including a set of contacts responsive to the accidental or intentional opening of the associated door, to immediately stop the generation of high-frequency energy within the device. However, if the door switch and the associated components are shifted from their exact positions, though the shift is very small, the prior art devices may malfunction and permit the high-frequency energy to leak externally of the device. Alternatively, the opening of the door might result in the door switch remaining open so that the heating operation cannot be realized.

SUMMARY OF THE INVENTION Accordingly, it is an object of the invention to eliminate the disadvantages of the prior art practice as above described by the provision of an electronic cooking device comprising, in combination, a housing, a heating compartment disposed within the housing and including an opening on the front face of the housing, a door pivotably secured to the housing to close and open the opening, a door arm pivotably mounted at one end to the door and fixedly secured at the other end to the housing through a spring serving to normally bias the door toward its closed position, a guide rollersecured to the housing to respond to the opening and closing of the door to guide the door arm to effect rocking movement about said one end, and a door switch secured to the housing adjacent the door arm and including a set of contacts operative in accordance with the rocking movement of the door arm.

It is another object of the invention to provide an electronic cooking device of the type as described in the preceding paragraph wherein the door arm includes a projection adapted to ride on the guide roller upon opening the door, thereby to open the contacts of the door switch.

It is still another object of the invention to provide an electronic cooking device of the type as described in the preceding paragraph wherein the guide roller and the door switch are preliminarily disposed in place on a baseplate thereby preventing the door switch from operating with a time delay resulting from displacements in their mounting positions.

BRIEF DESCRIPTION OF THE DRAWING The invention will become more readily apparent from the following detailed description taken in conjunction with the accompanying drawing in which:

FIG. 1 is a diagrammatic elevational, longitudinal sectional view of an electronic cooking device constructed in accordance with the principles of the prior art;

FIG. 2 is a view similar to FIG. 1 but illustrating one embodiment of the invention;

FIG. 3 is a fragmental view in enlarged scale of the door switch and the associated components shown in FIG. 2; and

FIG. 4 is a fragmental perspective view of a modification of the arrangement shown in FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIG. 1 of the drawing, it is seen that an electronic cooking device disclosed herein comprises a housing 10, a heating compartment 12 disposed within the housing 10 and including an opening on the front face or the left-hand. face as viewed in FIG. I of the housing 10, an openable door 14 pivotably mounted at the lower end as viewed in FIG. I to the front face of the housing 10, and a source 16 for generating high-frequency energy such as a magnetron disposed on the outer surface of the upper wall as viewed in FIG. I of the heating compartment 12 and having a high-frequency antenna shown at dotted line 18 as projecting into the compartment 12.

A door switch 20 is fixed to an upper portion as viewed in FIG. 1 of a mounting plate 22 fixed at the lower end to the bottom wall of the housing 10. The door switch 20 has an actuator 20a operatively coupled thereto on that side thereof facing the door 14 in its closed position. Then a door arm 24 is pivotably mounted at one end to the door I4 and extends toward the door switch 20 until its end abuts against the actua tor 204. That end portion adjacent the door 14 or the front end portion of the door arm 24 is supported by a guide roller 26 which is, in turn, rotatably carried on a pin 28 held on a mounting plate 30 fixed to the front face portion of the housing 10. The rear end portion of the door arm 24, or that portion adjacent to the actuator 20a has anchored thereon one end of a spring 32 having its other end anchored to the bottom wall of the housing 10 adjacent the lower'end of the mounting plate 22. The spring 32 serves to pull the door arm 24 to normally maintain the door 14 in its closed position as shown in FIG. 1.

With the door 14 put in its closed position, the rear end of the door arm 24 pushes against the actuator 20a for the door switch 20 to maintain the switch 20 in its closed position to supply power to keep the source 16 in operation. The terms rear and front" mean respectively those portions more remote from and nearer to the left-hand face as viewed in FIG. 1 of the housing 10. If the door is open the actuator 20a is released from a pressure provided by the doorarm 24 due to the spring 32 to bring the door switch 20 into its open position, thereby stopping the operation of the source I6.

In the arrangement of FIG. 1, the door switch 24 is positioned in the rear of the door arm 24 which, in turn, responds to the opening and closing of the door 14 thereby to operate the door switch 20 by the rear end thereof. If the door switch 20, the mounting plate 22 therefore, and the roller 26, etc, have been assembled in erroneous positions, though differences between the erroneous and correct positions are very small, the door switch 20 may remain closed after the door 14 has been fairly opened, thus resulting in the external leakage of the high-frequency energy; or, the switch may remain open upon closure of the door I4, thus resulting in the impossibility of performing the heating operation.

The invention contemplates elimination of the disadvantages of the prior art practice as above described, and FIGS. 2 and 3, wherein like reference numerals designate the components identical or similar to those shown in FIG. I illustrate one embodiment of the invention. The door arm 24 includes one end pivotably mounted to the door 14 and the other end having anchored thereat one end of the spring 32 including the other end anchored to the bottom wall of the housing. The spring 32 serves to pull the door arm 24 to normally maintain the door 14 at its closed position as in-the arrangement of FIG. I.

As best shown inFIG. 3, the door arm 24 is provided on the lower side of its intermediate portion with a protrusion 24a. When the door is closed the protrusion 24a pushesagainst a pushbutton 20a for the door switch 20 disposed .below the door arm 24, by action of the spring 32. Also the guide roller 26 is rotatably mounted on the pin 28 on thatside of the door switch 20 facing the opening of theheating compartment 12. With the door 14 put in its closed position, the protrusion24a is positioned in the front of the door switch 20, and the tilted transition portion thereof is disposed in pressure contact with the roller 28 by the action of the spring 32. In other respects the arrangement is identical to that shown in FIG. 1.

Thus, as in solid lines in FIG. 3, the protrusion 24a is positioned directly behind the roller 26 to push against the pushbutton a to put the door switch 20 in its closed position. This causes the source 16 to be maintained in the oscillation mode of operation.

Then if the door 14 is open as shown-at dotted-and-dashed line in FIG. 3, the door arm 24 rides on the roller 26 while it is forwardly moved to its position as illustrated at dotted-anddashed lines in FIG. 3. This permits the pushbutton 20a to be free from a pressure applied thereto by the protrusion 24 due to the spring 32, and to be upwardly moved to its position as illustrated at dotted-and-dashed lines in FIG. 3 with the result that power is removed from the source 16 so that its oscillation is stopped.

It is noted that a slight opening of the door 14 only, through a small angle, causes the door arm 24a to be moved substantially in an upward and forward direction to immediately disengage the door switch 20, so that the door switch 20 can be sensitively operated.

The arrangement of FIG. 3 can be improved as shown in FIG. 4 wherein like reference numerals designate the components identical to those shown in FIG. 3. In FIG. 4, the roller pin and door switch 28 and 20 respectively have been preliminarily disposed in place on a single baseplate 40. Thereafter, the baseplate 40 is fixedly secured in place on the outer wall surface of the heating compartment 12 as shown in FIG. 4. Therefore, upon manufacturing the baseplates 40, any suitable punch with a desired pattern can be used to simultaneously punch the holes for mounting the components at the exact positions on the baseplates. This measure permits the roller pin and door switch 28 and 20 respectively to be disposed in place on each baseplate with a high accuracy without the necessity of particularly taking care of the positional relationship therebetween upon disposing them on the baseplate. This configuration ensures that the door switch may be operated without malfunction.

The invention has several advantages. For example, only the slight opening of the door permits the door switch to be sensitively operated. With the devices manufactured on the basis of mass production, the door switches are not at all different in operating position from one another and therefore no malfunction is encountered. Also it eliminates the necessity of painstaking adjustment of the door switch and the mounting plate. This facilitates assembly operations and the saving of the working hours and material costs leading to a reduction in manufacturing costs.

While the invention has been illustrated and described in conjunction with a few preferred embodiments thereof it is to be understood that various changes and modifications may be resorted to without departing from the spirit and scope of the invention. For example, the invention is equally applicable to switch mechanisms responsive to the opening of the associated doors to energize a lamp for illuminating the interior of the associated heating compartment and other switch mechanisms operative in response to the opening and closing of the associated doors.

What is claimed is:

1. In an electronic cooking device, the combination comprising a housing, a heating compartment disposed within said housing and including an opening on a front face of said housing, a door pivotably secured to said housing to open and close the compartment opening, a door arm pivotably mounted at one end to said door, a spring for normally biasing the door toward its closed position and having one end connected to said housing and its other end connected to the other end of the door arm, a guide roller secured to said housing and disposed in engagement with said door arm to respond to the opening and closing of said door to guide said door arm to effect a rocking movement of said door arm about said one end thereof, and a switch secured to said housmg and including a set of contacts operative in response to the rocking movement of said door arm, wherein said door arm is provided on an intermediate portion thereof with a protrusion disposed at a position directly behind that portion of the door arm engaging against said guide roller upon closure of said door, said protrusion on said door arm responding to the opening of said door to ride on said guide roller, and wherein said door switch includes a pushbutton for actuating said door switch, said pushbutton being disposed at a position where said protrusion pushes against said pushbutton to close the contacts upon closure of said door.

2. In an electronic cooking device, the combination comprising a housing, a heating compartment disposed within said housing and including an opening on a front face of said housing, a door pivotally secured to said housing to open and close the compartment opening, a door arm pivotably mounted at one end to said door, a spring for normally biasing the door toward its closed position and having one end connected to said housing and its other end connected to the other end of the door arm, a guide roller mounted within said housing and disposed in engagement with said door armto respond to the opening and closing of said door to guide said door am to effect a rocking movement of said door arm about said one end thereof, a switch mounted within said housing and including a set of contacts operative in response to the rocking movement of said door arm, and a baseplate having said guide roller and said door switch preliminarily disposed in place thereon, said baseplate being fixed on an outer wall surface of said compartment. 

1. In an electronic cooking device, the combination comprising a housing, a heating compartment disposed within said housing and including an opening on a front face of said housing, a door pivotably secured to said housing to open and close the compartment opening, a door arm pivotably mounted at one end to said door, a spring for normally biasing the door toward its closed position and having one end connected to said housing and its other end connected to the other end of the door arm, a guide roller secured to said housing and disposed in engagement with said door arm to respond to the opening and closing of said door to guide said door arm to effect a rocking movement of said door arm about said one end thereof, and a switch secured to said housing and including a set of contacts operative in response to the rocking movement of said door arm, wherein said door arm is provided on an intermediate portion thereof with a protrusion disposed at a position directly behind that portion of the door arm engaging against said guide roller upon closure of said door, said protrusion on said door arm responding to the opening of said door to ride on said guide roller, and wherein said door switch includes a pushbutton for actuating said door switch, said pushbutton being disposed at a position where said protrusion pushes against said pushbutton to close the contacts upon closure of said door.
 2. In an electronic cooking device, the combination comprising a housing, a heating compartment disposed within said housing and including an opening on a front face of said housing, a door pivotally secured to said housing to open and close the compartment opening, a door arm pivotably mounted at one end to said door, a spring for normally biasing the door toward its closed position and having one end connected to said housing and its other end connected to the other end of the door arm, a guide roller mounted within said housing and disposed in engagement with said door arm to respond to the opening and closing of said door to guide said door arm to effect a rocking movement of said door arm about said one end thereof, a switch mounted within said housing and including a set of contacts operative in response to the rocking movement of said door arm, and a baseplate having said guide roller and said door switch preliminarily disposed in place thereon, said baseplate being fixed on an outer wall surface of said compartment. 